That's according to a report from the Drug Enforcement Administration. It also found the overall number of reported heroin users nearly tripled between 2007 and 2014.

In 2010, just over 3,000 people died from heroin overdoses, and that number rose to more than 10,500 in 2014.

The DEA says in the report that some heroin users turned to the drug because it's less expensive and sometimes easier to obtain than prescription painkillers.

Another rising problem in the U.S. is fentanyl. It can be disguised as prescription pills because of the high demand for painkillers. However, its much stronger than other drugs like heroin, which makes the chance of an overdose much higher.